A Mini-Lesson

EVOLUTION

Classification

SYNOPSIS

The module begins by introducing the three
domains of life: bacteria, archaea and eukaryotes, and explains
that all living things share a common ancestor. By understanding
this single unifying concept, students are able to understand
the evolutionary history and relationships of all
living things. Students are introduced to the process of illustrating
evolutionary relationships with branching diagrams called cladograms.
Students learn that once a cladogram has been constructed for
a group of organisms, it can be used to answer all kinds of interesting
questions based on the shared inherited features of those organisms.

CONCEPTS

* All living things are related
by common ancestry.
* Branching diagrams, called cladograms, are used to illustrate
evolutionary relationships.
* Cladograms are based on shared, inherited features.
* Cladograms refine our ability to understand and interpret evolutionary
history.

STUDENT HANDOUTS

TEACHING STRATEGY

This excellent online tutorial introduces students to the
family tree and lineage concepts, and extends this
to the tree of all life. It takes students through the
concepts of common ancestry, shared traits, unique
traits, and cladograms (reading, making cladograms,
adding new organisms to a cladogram, and making inferences about
new organisms).

CONTEXT:
This lesson would provide an excellent introduction to classification,
taking students from the familiar of family trees to the phylogenies
of the living world, and the evolutionary implications of that
tree. Basic concepts of cladograms are introduced to transition
from classification to introduction to evolution.

ATTRIBUTION

Some of the ideas in this lesson may have been adapted from
earlier, unacknowledged sources without our knowledge. If the
reader believes this to be the case, please let us know, and
appropriate corrections will be made. Thanks.